1. Field of the Invention
This invention relates to a method for making multi-layered shingles, and to roofing shingles made thereby. The shingles are uniquely thickened to enhance the appearance of a roof.
2. Description of the Prior Art
There have been many approaches by the roofing industry to the task of covering a roof deck with shingles which are both protective and aesthetically pleasing. Whatever their appearance, suitable shingles have been made sufficiently durable and weatherproof for prolonged protection of the roof. The shingles' visual appeal has been attained in various ways, such as by providing particular butt edge contours and surface treatments which function to simulate more traditional, and in most cases more expensive, forms of roof coverings, including thatch, wooden shakes, slates, and even tiles of various forms.
Simulation of such more traditional roof coverings is afforded by asphalt shingles of the laminated type. These shingles provide depth or its appearance on the roof, thus more or less giving the look of the wood or other natural appearing shingles. U.S. Pat. No. 3,921,358 provides an example of such composite shingles. After describing the futile attempts in the past to achieve the irregular, bulky, butt edge profile and surface contour characteristic of wood roofing shingles, this patent presents an improved composite shingle comprising a rectangular sheet having a headlap portion and a butt portion. The butt portion is divided into a series of spaced apart tabs and a strip is secured to the sheet in a position underlying the tabs and filling the spaces therebetween. While the resultant bilaminate structure suggests somewhat the substantial and imposing architectural appearance of the more expensive roofing materials, such as wood shingles, the structure still diverges considerably in appearance from them.
For many years roofing manufacturers have offered a variety of two-layered shingles of the type disclosed in U.S. Pat. No. 3,921,358 in the attempt to present a thicker and more attractive appearance. A structure markedly different from these prior art bilaminate shingles is shown in U.S. Pat. No. 4,869,942. This structure, which has an exposed butt portion three layers in depth, with tabs two layers in depth, and an additional strip under the cut-outs, gives the shingle an appearance that goes well beyond the bilaminates in simulating wood and tile shingles.
Although the asphalt composite shingles have significant cost, service life and non-flammability advantages over wood shingles, the latter type are still seen by many to be a much more desirable roofing material for aesthetic purposes. A key reason for wood shingles' continuing aesthetic appeal stems from their greater thickness relative to the composite shingles, in spite of the many efforts in the past to simulate this thickness. Accordingly, it would be most beneficial to find ways to enhance the appearance of depth in the composite shingles without sacrificing these shingles' advantageous features.